Теплообмін

About 70 to 75% of the energy consumed by the elements of transmit modules (TM) for active phased antenna arrays (APAA) is converted into heat. This heat, if dissipated inefficiently, can cause the element base to overheat, thus reducing the reliability of the radar. The task of ensuring the normal thermal regime of TMs for APAAs is complicated by the large-scale integration of electronic components inside the TMs.

Up to 30% of the produced electricity is being spent on the lighting in Ukraine. Therefore, the problem of energy saving in lighting stands very seriously. Introduction of energy-saving technologies in the internal lighting systems will provide significant energy savings and improve the ecological condition by reducing atmospheric discharges of thermal power plants.

Using the experimental and theoretical approach both heat transfer and gas-dynamics of two complex vortex and swirling flows have been studied in details. New regularities regarding the local and average heat transfer have been established in the cylindrical channel with initial tangentially-inclined flow swirl at the stationary conditions, as well as in the radial rotating channel. The new similarity correlations have been obtained for the different boundary conditions arranged at the channel exit.

New complex mathematical model of heat transfer processes in conditions of evaporation-condensation systems (miniature heat pipes, thermosyphons and pulsating heat pipes) inner space decreasing was developed. Criterial relation for evaluation of miniature heat pipes heat transfer ability was obtained as a result of differential equations system and conditions of uniqueness analysis.

The research of the water dispersion parameters in impact with a hard dry and wetted surface was made. Noted best water spraying at surface with high roughness. This may be due to the difficulty of the air outlet from under flat (before impact) drops during impact. The share of dispersed liquid upon impact a teardrop-shaped expanding jet ( 40% of the water flow in the jet ) with wooden batten was investigated. Also was determined the radius of scattering droplets depending on the fall height and of the water flow consumption from the nozzle.

Gas turbine unit ( GTU) is the dominant type of drive gas transportation system of Ukraine. However, most of them morally and physically obsolete, leading to a waste of gas for its own needs, which in 2010 amounted to 4.9 billion m3. To improve gas turbine is to use the least expensive stoves (regenerator) for utilization of heat in the turbine exhaust gases at the same time regenerators at current levels of use are bulky often have low operational reliability.

The equalizations of thermal balance for the system «space vehicle – device – thermal control system – space environment» for a thermosensitive device taking into account heat transmission , realized by heat pipes, are theoretically grounded. On the basis of analysis of these equalizations for the boundary conditions of device function a new thermal conception of construction of the effective thermal control system of class of scientific devices, which have not own heat generation is offered and experimentally researched.

Study and analysis of existing information enabled the development of the construction of a new steel tube equal developed helical type for use as a heat transfer surface air heaters-regenerators for gas compressor units, which are used in compressor stations Ukrainian gas transport system. This surface has several advantages: production with cheaper technology – roller burnishing of circular tube with granular material or liquid for making backpressure inside the tube.

Experimental research of heat exchange is conducted during condensation of water, chladone of R-141b and mixtures of chladones of R-22 and R-407С in a horizontal pipe with the passive intensifiers of heat exchange – wire rings and wire longitudinal scope at the circular, расслоенном and asymmetric flow of phases. The field of temperatures is measured in the vertical section of the thick-walled test area, passing through circular intensifiers.